CVE-2016-6813 in CloudStack
Summary
by MITRE
Apache CloudStack 4.1 to 4.8.1.0 and 4.9.0.0 contain an API call designed to allow a user to register for the developer API. If a malicious user is able to determine the ID of another (non-"root") CloudStack user, the malicious user may be able to reset the API keys for the other user, in turn accessing their account and resources.
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Analysis
by VulDB Data Team • 02/02/2021
Apache CloudStack versions 4.1 through 4.8.1.0 and 4.9.0.0 contain a critical authorization flaw that enables privilege escalation through improper access control mechanisms. This vulnerability resides in the developer API registration functionality, specifically within the API call that handles API key management for user accounts. The flaw stems from insufficient validation of user permissions when processing requests to reset API keys for other users, creating a path for unauthorized access that directly violates the principle of least privilege and proper access control enforcement.
The technical implementation of this vulnerability allows a malicious actor to exploit the API key reset functionality by leveraging knowledge of another user's account identifier. When a user attempts to register for developer API access, the system should verify that the requesting user has appropriate authorization to modify the target account's credentials. However, the implementation fails to properly validate the relationship between the requesting user and the target account, enabling an attacker to craft requests that appear to originate from legitimate users while actually operating on different accounts. This represents a classic case of inadequate input validation and insufficient authorization checks, which aligns with CWE-285 for improper authorization and CWE-287 for improper authentication.
The operational impact of this vulnerability extends beyond simple credential theft, as it provides attackers with comprehensive access to target user accounts and their associated resources within the CloudStack environment. Once an attacker successfully resets API keys for another user, they can execute any API calls that the compromised user is authorized to perform, potentially leading to data exfiltration, resource manipulation, or unauthorized service consumption. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1078 for Valid Accounts and T1531 for Account Access Removal, as it enables attackers to assume legitimate user identities while simultaneously compromising the integrity of the authentication system.
Organizations utilizing affected CloudStack versions face significant risk of unauthorized account access and potential data breaches when this vulnerability remains unpatched. The attack vector requires minimal technical expertise and can be automated, making it particularly dangerous in environments where multiple users maintain accounts with varying privilege levels. The vulnerability's persistence across multiple version releases indicates a fundamental flaw in the API access control implementation that requires immediate remediation through proper authentication and authorization controls.
The recommended mitigation strategy involves implementing immediate patching of CloudStack installations to versions that address this authorization flaw, along with strengthening API access controls through proper session management and user authentication validation. Organizations should also consider implementing additional monitoring for unusual API key reset activities and establish robust audit trails for credential modifications. The fix should enforce strict user identity verification before allowing API key operations and ensure that all API calls properly validate the requesting user's authorization to act on behalf of target accounts. This vulnerability underscores the critical importance of proper access control implementation in cloud environments and the necessity of regular security assessments to identify similar authorization gaps in complex distributed systems.